The present invention relates to a wheel attitude control method for controlling wheel attitude when braking a vehicle by imparting a braking force to wheels attached to a vehicle and a wheel attitude control device using the method.
When braking a vehicle by imparting a braking force to wheels, each of front wheels undergoes an increase in load due to this braking, and a camber angle and a toe angle indicating wheel attitude are changed. This change depends upon a wheel mounting link mechanism for wheel attachment. Generally speaking, in a case of a high load, a toe-out state tends to occur in which the wheels are widened outwardly with respect to a vehicle advancing direction, with the wheel being in a negative camber state in which the wheel is inclined toward an inner side of the wheel with respect to a direction perpendicular to the contact patch.
When the vehicle is thus braked, the tire attitude is changed, and hence a shape of the contact patch where the tire is in contact with a road surface is deviated from the symmetrical shape, which exerts high braking force. As a result, there arises a problem in that it is impossible to maintain a high braking force.
JP 2005-343281 A discloses a method of and an apparatus for estimating tire dynamic state and a tire with sensors.
According to the above-mentioned publication, using a center position of a tire tread as a reference, strain gauges are mounted at two symmetrical positions in a tire width direction, and a contact length is obtained from an output waveform of the strain gauge, the load, lateral force, and longitudinal force being estimated from the obtained contact length.